Operation HARDTACK, a Joint Atomic Energy Commission-Department of Defense test series of nuclear weapons and devices was conducted by Commander, Joint Task Force SEVEN at the Eniwetok Proving Ground during the spring and summer of 1958. The Chief of Staff of the United States Air Force was the Executive Agent of the Joint Chiefs of Staff for the conduct of the test series. The Naval participation in this Operation was provided by Task Group 7.3. Thirty-five detonations took place at Eniwetok, Bikini and Johnston Island. A listing of all shots is appended to this section. The peak strength of Task Group 7.3 consisted of 6,822 personnel. A ship rotation policy increased the number of Naval Personnel who were able to receive indoctrination and training in nuclear weapon tests to a total of 9,178.